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Advanced Endodontics

John S Rhodes qualified from Kings College London in 1990, where he was awarded the Claudius Ash prize in conservation and the Jose Souyave endodontic prize. He continued his postgraduate education at Guys Hospital London, where he achieved a distinction in the Endodontic MSc. He is registered on the GDC specialist list in endodontics and now runs a busy endodontic referral practice in Poole, Dorset. John S Rhodes lectures widely in the UK and provides numerous postgraduate endodontic courses. He has published research papers in several refereed journals and is co-author of the endodontic textbook Endodontics: Problem-Solving in Clinical Practice.

Advanced EndodonticsClinical Retreatment and SurgeryJohn S Rhodes BDS(LOND) MSC MFGDP(UK) MRD RCS(ED) Specialist in endodonticsThe Endodontic Practice Poole, UK

2006 Taylor & Francis, an imprint of the Taylor & Francis Group Taylor & Francis Group is the Academic Division of Informa plc First published in the United Kingdom in 2006 by Taylor & Francis, an imprint of the Taylor & Francis Group, 2 Park Square, Milton Park, Abingdon, Oxon OX14 4RN Tel: Fax: E-mail: Website: 44 (0)20 7017 6000 44 (0)20 7017 6699 [email protected]

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior permission of the publisher or in accordance with the provisions of the Copyright, Designs and Patents Act 1988 or under the terms of any licence permitting limited copying issued by the Copyright Licensing Agency, 90 Tottenham Court Road, London W1P 0LP. Although every effort has been made to ensure that all owners of copyright material have been acknowledged in this publication, we would be glad to acknowledge in subsequent reprints or editions any omissions brought to our attention. Although every effort has been made to ensure that drug doses and other information are presented accurately in this publication, the ultimate responsibility rests with the prescribing physician. Neither the publishers nor the authors can be held responsible for errors or for any consequences arising from the use of information contained herein. For detailed prescribing information or instructions on the use of any product or procedure discussed herein, please consult the prescribing information or instructional material issued by the manufacturer. A CIP record for this book is available from the British Library. Library of Congress Cataloging-in-Publication Data Data available on application ISBN 1-84184-436-5 ISBN 978-1-84184-436-7 Distributed in the United States and Canada by Thieme New York 333 Seventh Avenue New York, NY 10001 Distributed in the rest of the world by Thomson Publishing Services Cheriton House North Way Andover Hampshire SP10 5BE, UK Tel: 44 (0)1264 332424 E-mail: [email protected] Composition by Newgen Imaging Systems (P) Ltd, Chennai, India Printed and bound in Great Britain by CPI, Bath


Acknowledgements Preface Dedication 1 2 3 4 5 6 7 8 9 10 Index Rationale for endodontic retreatment Decision making and treatment planning Dismantling coronal restorations Removal of pastes, gutta percha and hard cements Removal of silver points and separated instruments Perforation repair and renegotiating the root canal system following dismantling Irrigation and medication Introduction to surgical endodontics Pain control, haemostasis and flap design Surgical procedures

vi vii viii 1 23 45 67 89 113 129 147 163 177 201


I wish to thank the following for kind permission to reproduce figures: Dr CP Sproat: Figure 8:15 Dr J Aquilina: Figures 6:18 and 6:19 Mr DA Oultram (Optident UK): Figures 7:09, 7:10 Mr S Bonsor, Mr G Pearson and Mr J Williams: Figures 7:11, 7:12, 7:13 I would like to acknowledge the contributions of the following people and companies who provided equipment for photography: Neil Conduit of QED, Douglas Pitman of DP Medical, David Mason of J&S Davis, Dentsply UK, Henry Schien UK, Optident and Denfotex; the staff at The Endodontic Practice who agreed to be photographed for illustrative material; my parents, who helped edit the many drafts; and my wife Sarah and family, who supported me patiently while I compiled this book.


This book is intended for the general practitioner with a special interest in endodontics, students undergoing specialist training and specialists alike. Endodontic retreatment poses many practical challenges. Advances in scientific knowledge and the integration of operating microscopes into endodontic practice have seen the possibilities for predictable endodontic treatment and retreatment expand dramatically. Advanced Endodontics: Clinical Retreatment and Surgery describes many of the techniques and methods available for practitioners who wish to undertake the planning and treatment of complex endodontic retreatment. The pages are copiously illustrated with high-quality photographs and case reports which are used to demonstrate practical non-surgical and surgical techniques. The text is referenced to provide a comprehensive but discreet source of scientific evidence, principles and further reading. Knowledge and theory are important in managing complex endodontic retreatment cases, but cannot be a substitute for essential practical and clinical experience. These skills need to be learned and practiced. Novices should always start with the simplest cases and never proceed beyond their confidence or skill level. Numerous practical courses are available for instruction on retreatment techniques and attendance on them can only be encouraged. John S Rhodes


This book is dedicated to my endodontic mentors: Professor Tom Pitt Ford and Dr Chris Stock

1 RATIONALE FOR ENDODONTIC RETREATMENTCONTENTS Introduction Biological Failings Cysts Cracked Teeth and Fractures Incorrect Diagnosis and Treatment Foreign Body Reactions Healing with Scar Neuropathic Problems Economic Constraints Conclusion References

INTRODUCTIONPatients increasingly expect to retain their natural dentition and are often reluctant to have teeth extracted. Endodontic retreatment or surgery may offer the patient a second chance to save a root-treated tooth that would otherwise be destined for extraction. The success rate for root canal treatment carried out with currently accepted principles should be high. Indeed, published figures of between 70 and 95% have been quoted in studies using samples derived from teaching hospitals.1 However, there is marked variation in the ability of operators to achieve successful results. Some studies using data collected from general practice have shown relatively low success rates for root canal treatment. An assessment into the standard of root canal treatment in England and Wales for example, showed that 97% of molar root canal treatment and 84% of canine and incisor root canal treatment had technical difficulties,2 whereas in Scotland over 58% of root filled teeth showed signs of periapical radiolucency.3 Similar radiographic results have been found in studies from the USA4 and Holland.5 The prevalence of endodontically treated teeth showing periradicular radiolucency in Scandinavia has consistently been reported to be between 25 and 35%.6 Obviously, there is a contradiction between what is achievable and what is actually achieved. So why does primary endodontic treatment fail?

Endodontic failure comprises: biological failings (infection) cysts root fracture incorrect diagnosis and primary treatment foreign body reactions healing with scar neuropathic problems economic constraints.

BIOLOGICAL FAILINGSThe most common reason for failure of root treatment is microbial infection. Microorganisms and their byproducts have been isolated from the root canal system and the external surface of the root in failed cases. They may have persisted following a previous attempt at root canal treatment or gained access through coronal microleakage.

Intraradicular InfectionIt is well documented in clinical studies that teeth with technically deficient root fillings are more likely to be associated with periapical radiolucencies. If a root filling is of poor quality, the root canal system may not have been effectively disinfected or could have become reinfected through coronal microleakage (Figures 1.1, 1.2). The apical portion of the root canal system can contain bacteria and necrotic tissue



Figure 1.1 This radiograph shows a chronic periapical lesion associated with the maxillary left first premolar. The tooth has been restored with a post and core and is an abutment for a bridge. There is little root filling material present and the root canal would undoubtedly be infected. Figure 1.2 In this case the maxillary right first molar has been root filled. The root filling material is short in the mesiobuccal and palatal roots but there is little evidence of periapical pathology. The distobuccal canal has a fractured stainless steel instrument in it. The root canal must be infected, as there is a periapical radiolucency present. The root canal system may have become reinfected by coronal microleakage following root canal treatment because the file provided a poor seal. Alternatively, infected material may not have been removed or could have been carried along the entire length of the root canal prior to the instrument failing. Sufficient numbers of bacteria are now present to cause persistence of the lesion.

substrate even following chemomechanical preparation.7,8 If the resultant microbial ecosystem is amenable to bacterial surviv